The cabin noise level in a transport category aircraft is typically a combination of several energy sources such as engine noise, engine vibration, turbulent boundary layer, air-conditioning machinery noise, and the like. The noise sources enter the aircraft cabin through different paths, the two major paths being an air-borne path and a structural-borne path. The interior trim panels of an aircraft cabin have a relatively large surface area and are usually fabricated from lightweight materials having low noise damping properties. These three characteristics in a single structural element, namely lightweight, low damping material and large surface area, therefore cause the interior trim panels to play an important role in the structure-borne path, and consequently in the aircraft cabin noise levels that are experienced. One of the most common noise control techniques used in current interior aircraft cabin design is to physically attach pieces of viscoelastic material onto the back of the interior trim panel in order to impose some noise damping properties on the panel.
Various proposals exist in the art to enhance the vibro-acoustic properties of aircraft interior trim panels, such as those described in US Published Application No. 2010/148001, US Published Application No. 2014/0299409 and U.S. Pat. No. 8,087,494, the entire contents of each being expressly incorporated hereinto by reference. One principal disadvantage of such prior proposals, however, is that the mechanical properties of the panels are jeopardized due to discontinuities in the junction of the core and cover layers.
What has been needed in the art, therefore, are aircraft interior cabin panels that exhibit improved acoustic damping and mechanical properties. It is towards fulfilling such needs that the embodiments disclosure herein are directed.